Total shot in the dark. I remember a British film from the 70s about a girl (aged 9-10) making friends with a large (6ft ish) rabbit only she could see. He was dressed in a waist coat and could talk. She had a bratty little sister (6-7) who screamed a lot! I remember a birthday party held for the older girl. Also near the end other people started to see the giant rabbit. Hope someone knows the title and if it's still out there. Worth watching again!

Mr. Horatio Knibbles

THANK YOU!!!!! That's It!